Thou art one of them that trouble me: before this, I was troubled by my brethren; and since, by the Ammonites; and now most of all, though but occasionally, by thee. I have opened my mouth, i.e. I have vowed, which was done by words, Num_30:2,6.
I cannot go back, i.e. not retract my vow; I am indispensably obliged to perform it.